Straub had developed it during a research stay at the Stazione Zoologica in Naples at the start of the new century. There, he studied the antagonism between atropine and the poison of the fly agaric, muscarine, on the heart of the sea snail (Aplysia) and the torpedo fish. In essence, he argued that a poison acted as long as there was a concentration difference or ‘potential’ between the outside and the inside of the cell. The effect was due to a deformation or other physical disturbance of the cell membrane when the poison molecules penetrated it. Like Langley, Straub was quick to generalize, suggesting that his physical theory of drug action applied also to other alkaloids, such as pilocarpine, physostigmine and nicotine, and to the hormone adrenalin [17]. Straub's theory found significant supporters in Britain, in particular Henry Dale (1875–1968) and George Barger (1878–1939) of the Wellcome Physiological Research Laboratories and Arthur Cushny (1866–1926), who held the chair in pharmacology at University College London [18].